Apparatus for determining sulphur



Dec. 11, 1955 c. a. FRANCIS APPARATUS FOR DETERMINING SULPHUR OriginalFiled Feb. 9, 1950 CARBON DETERMINING APPARATUS unar/111111111, 1,

INVENTOR. CHARLES B. FRANCIS FURNACE HIS ATTORNEY United States PatentAPPARATUS FOR DETERNHNTNG SULPHUR Charles B. Francis, Pittsburgh, Pa.

Original application February 9, 1950, Serial No. 143,054,

new Patent No. 2,639,980, dated May 26, 1953. Digildegzasnd thisapplication October 22, 1952, Serial No.

1 Claim. (Cl. 23-259) This invention, which is a division of myco-pending application, Serial No. 143,054, filed February 9, 1950, nowPatent No. 2,639,980, dated May 26, 1953, relates to apparatus ifOl'determining the amount of sulphur and oxides thereof in variousmaterials such as in iron and ferrous alloys. In the determination ofsulphur :by the apparatus commonly used at present the sample isdestroyed so that it is necessary to provide a second sample when it isdesired to further analyze the material such as for the amount of carbonin the sample. Also, in the apparatus presently used the sulphurd-ioxides will be absorbed but the sulphur trioxides will not beabsorbed.

It is therefore an object of my invention to provide apparatus fordetermining sulphur and oxides thereof in a sample in such a manner thatother tests may :be made on the sample.

This and other objects he more apparent after referring to the followingspecification and attached drawings, in which:

Figure 1 is a schematic view of the apparatus of my invention;

Figure 2 is a sectional view taken on the line H ll of Figure 1; and

Figure 3 is a schematic view of a second embodiment of my invention.

Referring more particularly to Figure =1 of the drawings, referencenumeral 2 discloses 'a conventional high temperature tube furnace. Thetube of this furnace is made of highly refractory non-porous materialthat will withstand temperatures up to 3000 F. without softening. Thetube preferably has an internal diameter not exceeding 25 mm. and :alength not exceeding 760 mm. A refractory boat containing the sample ofsteel to be analyzed is placed in this tube and the sample is completelyoxidized by passing oxygen through the hot tube. A conduit 4 extendsfrom the furnace 2 to a filter 6 which may be a glass tube 8 packed withcotton 10. A conduit 12 leads from the filter 6 to the sulphur analyzingunit of my invention which consists of a special absorption vessel 14having a mark 15 thereon, two threeway stop cocks 16 and 18, a silvernitrate reservoir 20, a water reservoir 22, and a beaker 24. Thethree-way stop cocks 16 and 18 are connected in the conduit 12 and areconnected by conduits 26 and 28 to the reservoirs and 22, respectively.The special absorption vessel 14 has a gas dispersing tube 30 thereinwhich has one end connected to the stop cock 16 and its other endterminating adjacent a stop cock 32 at the lower end of the absorptionvessel 14. The vessel 14 is provided with a bulbous portion 34 forreceiving a similar bulbous portion 36 on the tube 30. The bulbousportion 36 is provided with small openings '38 spaced around itsperiphery. The top part of the vessel 14 is provided with a stop cock40. In its normal position the stop cock 40 connects the interior of thevessel 14 to a conduit 42 which leads to a carbon absorption unit B suchas disclosed in my above mentioned patent. By turning stop cock 4t)counterclockwise through :an angle of 45 the exit to 2,773,748 PatentedDec. 11, 1956 "ice conduit 42 is closed and :by turning it clockwisethrough "an angle of 45 the interior of the vessel 14 is connected tothe outside air through a second conduit 44 as best shown in Figure 2.This second conduit 44 is preferably connected by means of a rubber hose46 to the beaker 24 which is located beneath the vessel 14.

In some instances the absorption tube '14 may be made in a difierentmanner than shown in Figure 1. As shown in Figure 3, the absorption tube14 is replaced -by a tube having a cylindrical upper portion 102 ofsufiicient diameter to admit the dispersing tube 30. The upper portion102 is partly filled with glass beads 104 to occupy about 60% of thespace.

The procedure followed in determining the amount of sulphur in steel isas follows:

The sample is prepared in the usual manner and a known amount, such as2.4 grams thereof, is placed in the combustion boat which in turn isplaced in the combustion tube in the furnace 2. Between 5 and 10 ml. ofsilver nitrate solution is introduced into the absorber $1 4 from thereservoir 20, thus causing the silver nitrate to rise to the mark 15 onthe wall of absorber 14. The sample is then ignited in the furnace 2 andstop cocks 16 and 18 turned to the position shown in Figure l. The gasevolved passes through conduit 12 through the gas dispersing tube 30 andthe openings 38 into the silver nitrate in the vessel 14. The silvernitrate will :absorb the sulphur oxides evolved. If the sample is :beinganalyzed for carbon or other material the gases will pass through theconduit 42 to the carbon dioxide absorbing apparatus B and the gas isanalyzed in the manner set forth in my above mentioned copendingapplication. The sulphur is oxidized to form sulphur dioxide, with thepossibility that some of the S02 is catalytically oxidized to sulphurtrioxide 803. These gases are capable of uniting with metallic oxides toform sulfites and sulfates which are held in solution by the liquid orsemi fluid slag formed. Consequently, only a part of the sulphur escapesas $02 during and immediately following the combustion, [and theremainder is evolved more slowly from the slag as the sulfates andsulfites are decomposed by heat from the furnace. This is not true ofthe oxides of carbon and the carbon analysis can be run while theevolution of vthe sulphur oxides continues. After (all the carbon hasbeen oxidized to carbon dioxide the stop cock 40 is turned to shut oilthe flow of gas to conduit 42 and to exhaust the gas through tube 46 tobeaker 24. The rate of flow of the oxygen into the furnace 2 is thenincreased to evolve the remainder of the sulphur.

To find the percent sulphur in the gas, the oxygen flow is turned off atthe end of five minutes or after all the sulphur has evolved, and stopcook 32 is turned to permit the silver nitrate solution in the absorber14 to flow into the titrating beaker 24. To rinse the absorber, stopcock 32 is closed and stop cock 1 -8 is turned to connect with the waterreservoir =22 until the absorber 1-4 is filled with water, after whichstop cock 18 is closed and stop cock 32 is opened, thus permitting therinse Water to flow into the titrating beaker 24. After the addition ofone or two drops of an indicator solution, the acid equivalent to thesulphur in the sample is titrated with a standard solution of sodiumhydroxide (approximately 5 thousandths normal) from a burette. Thenumber of milliliters of this solution used to titrate the silvernitrate solution, divided by three, gives the sulphur content of thesample in hundredths of a percent.

The carbon determining apparatus B is then prepared for determining theamount of carbon in the following sample in the manner set forth in myabove mentioned copending application. Stop cock 40 is then turned toconnect with the atmosphere. Stop cock 32 is closed and stop cock 16 isturned to admit silver nitrate solution from reservoir 20 until theliquid rises to the mark 15 on the wall of absorber 14. Stop cocks 16and 18 are-then tion tube and placed under cover to "coolyafiteri"which" the apparatus is ready to receive another sample. 7

While several embodiments of my invention have been shown and describedit will be apparent that other adaptations and modifications may be madewithout departing from the scope of the following claim.

Apparatus for absorbing in a liquid a gas from a mixture of gasescomprising an elongated vessel, the top section of said vesselhaving twooutlets,a three-way stop cock in said top section for control-lingflowof gas to said outlets, said three way stop cock being movable to oneposition to prevent escape of gas from said vessel and to anotherposition to permit flow of unabsorbed gases therefrom, the bottomsection 0t said vessel having an opening therein, a stop cock in saidbottom section, said last named stop cock being movable to one positionto close said opening and to another position to permit flow of liquidtherefrom, a gas dispersing tube in said vessel, said tube having abulbous portion intermediate its ends with openings therein, the bottomof said tube being open and extending to a point above the last namedstop cock, and the top of said tube extending through the wall of saidvessel below the top thereof, said tube adapted to be connected to saidmixture of gases, a second threeway stock cock, a third three-way stopcock, said second and third three-way stop cocks being positioned in theportion of said tube outside said vessel, a reservoir adapted to containgas absorbing liquid, a reservoir adapted to contain a rinsing liquid, aconnection between the second three-way stop cock and the first namedreservoir, and a connection between the third three-way stop cock andthe last named reservoir, said second threeway stop cock being movableto one position to permit flow of absorbing liquidto .said vessel and toanother position to stop flow of absorbing liquid and permit flow of themixture of gases to said vessel, said thirdthree-way stop cock beingmovable to one position to permit flow of rinsing liquid to said vesseland to another position to stop flow of rinsing liquid andpermit flow ofthe mix: ture of .gasesto said vessel.

References Cited in the file of this patent UNITED STATES PATENTS1,074,795 Johnson Oct. 7, 1913 1,668,362 Francis May l, 1928 1,877,151Turner Sept. 13, 1932 2,014,823 Tram Sept. 17, 1935 2,045,866 MorrisonJune 30, 1936 2,224,044 .Franois et a1. Dec. 3, 1940 2,336,075 Derge -4'Dec. 7,- 1943 2,462,293 Thomas Feb. '22, 1949 2,585,314 Hazeltine Feb.13, 1952 2,610,107 Dreher Sept. 9, 1952 2,639,980 Francis May 26, 1953OTHER REFERENCES j A. S. T. M. Methods Chemical Analysisof Met-a ls,

1946, pages 1720; pub. by Am. Society for Testing Materials, 1916, RaceSt., Philadelphia 3, Pa.

